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tldr: refactoring
2019-12-16 18:12:10 +01:00
# -*- coding: utf-8 -*-
"""
babel.core
~~~~~~~~~~
Core locale representation and locale data access.
:copyright: (c) 2013-2019 by the Babel Team.
:license: BSD, see LICENSE for more details.
"""
import os
from babel import localedata
from babel._compat import pickle, string_types
from babel.plural import PluralRule
__all__ = ['UnknownLocaleError', 'Locale', 'default_locale', 'negotiate_locale',
'parse_locale']
_global_data = None
_default_plural_rule = PluralRule({})
def _raise_no_data_error():
raise RuntimeError('The babel data files are not available. '
'This usually happens because you are using '
'a source checkout from Babel and you did '
'not build the data files. Just make sure '
'to run "python setup.py import_cldr" before '
'installing the library.')
def get_global(key):
"""Return the dictionary for the given key in the global data.
The global data is stored in the ``babel/global.dat`` file and contains
information independent of individual locales.
>>> get_global('zone_aliases')['UTC']
u'Etc/UTC'
>>> get_global('zone_territories')['Europe/Berlin']
u'DE'
The keys available are:
- ``all_currencies``
- ``currency_fractions``
- ``language_aliases``
- ``likely_subtags``
- ``parent_exceptions``
- ``script_aliases``
- ``territory_aliases``
- ``territory_currencies``
- ``territory_languages``
- ``territory_zones``
- ``variant_aliases``
- ``windows_zone_mapping``
- ``zone_aliases``
- ``zone_territories``
.. note:: The internal structure of the data may change between versions.
.. versionadded:: 0.9
:param key: the data key
"""
global _global_data
if _global_data is None:
dirname = os.path.join(os.path.dirname(__file__))
filename = os.path.join(dirname, 'global.dat')
if not os.path.isfile(filename):
_raise_no_data_error()
with open(filename, 'rb') as fileobj:
_global_data = pickle.load(fileobj)
return _global_data.get(key, {})
LOCALE_ALIASES = {
'ar': 'ar_SY', 'bg': 'bg_BG', 'bs': 'bs_BA', 'ca': 'ca_ES', 'cs': 'cs_CZ',
'da': 'da_DK', 'de': 'de_DE', 'el': 'el_GR', 'en': 'en_US', 'es': 'es_ES',
'et': 'et_EE', 'fa': 'fa_IR', 'fi': 'fi_FI', 'fr': 'fr_FR', 'gl': 'gl_ES',
'he': 'he_IL', 'hu': 'hu_HU', 'id': 'id_ID', 'is': 'is_IS', 'it': 'it_IT',
'ja': 'ja_JP', 'km': 'km_KH', 'ko': 'ko_KR', 'lt': 'lt_LT', 'lv': 'lv_LV',
'mk': 'mk_MK', 'nl': 'nl_NL', 'nn': 'nn_NO', 'no': 'nb_NO', 'pl': 'pl_PL',
'pt': 'pt_PT', 'ro': 'ro_RO', 'ru': 'ru_RU', 'sk': 'sk_SK', 'sl': 'sl_SI',
'sv': 'sv_SE', 'th': 'th_TH', 'tr': 'tr_TR', 'uk': 'uk_UA'
}
class UnknownLocaleError(Exception):
"""Exception thrown when a locale is requested for which no locale data
is available.
"""
def __init__(self, identifier):
"""Create the exception.
:param identifier: the identifier string of the unsupported locale
"""
Exception.__init__(self, 'unknown locale %r' % identifier)
#: The identifier of the locale that could not be found.
self.identifier = identifier
class Locale(object):
"""Representation of a specific locale.
>>> locale = Locale('en', 'US')
>>> repr(locale)
"Locale('en', territory='US')"
>>> locale.display_name
u'English (United States)'
A `Locale` object can also be instantiated from a raw locale string:
>>> locale = Locale.parse('en-US', sep='-')
>>> repr(locale)
"Locale('en', territory='US')"
`Locale` objects provide access to a collection of locale data, such as
territory and language names, number and date format patterns, and more:
>>> locale.number_symbols['decimal']
u'.'
If a locale is requested for which no locale data is available, an
`UnknownLocaleError` is raised:
>>> Locale.parse('en_XX')
Traceback (most recent call last):
...
UnknownLocaleError: unknown locale 'en_XX'
For more information see :rfc:`3066`.
"""
def __init__(self, language, territory=None, script=None, variant=None):
"""Initialize the locale object from the given identifier components.
>>> locale = Locale('en', 'US')
>>> locale.language
'en'
>>> locale.territory
'US'
:param language: the language code
:param territory: the territory (country or region) code
:param script: the script code
:param variant: the variant code
:raise `UnknownLocaleError`: if no locale data is available for the
requested locale
"""
#: the language code
self.language = language
#: the territory (country or region) code
self.territory = territory
#: the script code
self.script = script
#: the variant code
self.variant = variant
self.__data = None
identifier = str(self)
if not localedata.exists(identifier):
raise UnknownLocaleError(identifier)
@classmethod
def default(cls, category=None, aliases=LOCALE_ALIASES):
"""Return the system default locale for the specified category.
>>> for name in ['LANGUAGE', 'LC_ALL', 'LC_CTYPE', 'LC_MESSAGES']:
... os.environ[name] = ''
>>> os.environ['LANG'] = 'fr_FR.UTF-8'
>>> Locale.default('LC_MESSAGES')
Locale('fr', territory='FR')
The following fallbacks to the variable are always considered:
- ``LANGUAGE``
- ``LC_ALL``
- ``LC_CTYPE``
- ``LANG``
:param category: one of the ``LC_XXX`` environment variable names
:param aliases: a dictionary of aliases for locale identifiers
"""
# XXX: use likely subtag expansion here instead of the
# aliases dictionary.
locale_string = default_locale(category, aliases=aliases)
return cls.parse(locale_string)
@classmethod
def negotiate(cls, preferred, available, sep='_', aliases=LOCALE_ALIASES):
"""Find the best match between available and requested locale strings.
>>> Locale.negotiate(['de_DE', 'en_US'], ['de_DE', 'de_AT'])
Locale('de', territory='DE')
>>> Locale.negotiate(['de_DE', 'en_US'], ['en', 'de'])
Locale('de')
>>> Locale.negotiate(['de_DE', 'de'], ['en_US'])
You can specify the character used in the locale identifiers to separate
the differnet components. This separator is applied to both lists. Also,
case is ignored in the comparison:
>>> Locale.negotiate(['de-DE', 'de'], ['en-us', 'de-de'], sep='-')
Locale('de', territory='DE')
:param preferred: the list of locale identifers preferred by the user
:param available: the list of locale identifiers available
:param aliases: a dictionary of aliases for locale identifiers
"""
identifier = negotiate_locale(preferred, available, sep=sep,
aliases=aliases)
if identifier:
return Locale.parse(identifier, sep=sep)
@classmethod
def parse(cls, identifier, sep='_', resolve_likely_subtags=True):
"""Create a `Locale` instance for the given locale identifier.
>>> l = Locale.parse('de-DE', sep='-')
>>> l.display_name
u'Deutsch (Deutschland)'
If the `identifier` parameter is not a string, but actually a `Locale`
object, that object is returned:
>>> Locale.parse(l)
Locale('de', territory='DE')
This also can perform resolving of likely subtags which it does
by default. This is for instance useful to figure out the most
likely locale for a territory you can use ``'und'`` as the
language tag:
>>> Locale.parse('und_AT')
Locale('de', territory='AT')
:param identifier: the locale identifier string
:param sep: optional component separator
:param resolve_likely_subtags: if this is specified then a locale will
have its likely subtag resolved if the
locale otherwise does not exist. For
instance ``zh_TW`` by itself is not a
locale that exists but Babel can
automatically expand it to the full
form of ``zh_hant_TW``. Note that this
expansion is only taking place if no
locale exists otherwise. For instance
there is a locale ``en`` that can exist
by itself.
:raise `ValueError`: if the string does not appear to be a valid locale
identifier
:raise `UnknownLocaleError`: if no locale data is available for the
requested locale
"""
if identifier is None:
return None
elif isinstance(identifier, Locale):
return identifier
elif not isinstance(identifier, string_types):
raise TypeError('Unexpected value for identifier: %r' % (identifier,))
parts = parse_locale(identifier, sep=sep)
input_id = get_locale_identifier(parts)
def _try_load(parts):
try:
return cls(*parts)
except UnknownLocaleError:
return None
def _try_load_reducing(parts):
# Success on first hit, return it.
locale = _try_load(parts)
if locale is not None:
return locale
# Now try without script and variant
locale = _try_load(parts[:2])
if locale is not None:
return locale
locale = _try_load(parts)
if locale is not None:
return locale
if not resolve_likely_subtags:
raise UnknownLocaleError(input_id)
# From here onwards is some very bad likely subtag resolving. This
# whole logic is not entirely correct but good enough (tm) for the
# time being. This has been added so that zh_TW does not cause
# errors for people when they upgrade. Later we should properly
# implement ICU like fuzzy locale objects and provide a way to
# maximize and minimize locale tags.
language, territory, script, variant = parts
language = get_global('language_aliases').get(language, language)
territory = get_global('territory_aliases').get(territory, (territory,))[0]
script = get_global('script_aliases').get(script, script)
variant = get_global('variant_aliases').get(variant, variant)
if territory == 'ZZ':
territory = None
if script == 'Zzzz':
script = None
parts = language, territory, script, variant
# First match: try the whole identifier
new_id = get_locale_identifier(parts)
likely_subtag = get_global('likely_subtags').get(new_id)
if likely_subtag is not None:
locale = _try_load_reducing(parse_locale(likely_subtag))
if locale is not None:
return locale
# If we did not find anything so far, try again with a
# simplified identifier that is just the language
likely_subtag = get_global('likely_subtags').get(language)
if likely_subtag is not None:
language2, _, script2, variant2 = parse_locale(likely_subtag)
locale = _try_load_reducing((language2, territory, script2, variant2))
if locale is not None:
return locale
raise UnknownLocaleError(input_id)
def __eq__(self, other):
for key in ('language', 'territory', 'script', 'variant'):
if not hasattr(other, key):
return False
return (self.language == other.language) and \
(self.territory == other.territory) and \
(self.script == other.script) and \
(self.variant == other.variant)
def __ne__(self, other):
return not self.__eq__(other)
def __hash__(self):
return hash((self.language, self.territory, self.script, self.variant))
def __repr__(self):
parameters = ['']
for key in ('territory', 'script', 'variant'):
value = getattr(self, key)
if value is not None:
parameters.append('%s=%r' % (key, value))
parameter_string = '%r' % self.language + ', '.join(parameters)
return 'Locale(%s)' % parameter_string
def __str__(self):
return get_locale_identifier((self.language, self.territory,
self.script, self.variant))
@property
def _data(self):
if self.__data is None:
self.__data = localedata.LocaleDataDict(localedata.load(str(self)))
return self.__data
def get_display_name(self, locale=None):
"""Return the display name of the locale using the given locale.
The display name will include the language, territory, script, and
variant, if those are specified.
>>> Locale('zh', 'CN', script='Hans').get_display_name('en')
u'Chinese (Simplified, China)'
:param locale: the locale to use
"""
if locale is None:
locale = self
locale = Locale.parse(locale)
retval = locale.languages.get(self.language)
if retval and (self.territory or self.script or self.variant):
details = []
if self.script:
details.append(locale.scripts.get(self.script))
if self.territory:
details.append(locale.territories.get(self.territory))
if self.variant:
details.append(locale.variants.get(self.variant))
details = filter(None, details)
if details:
retval += ' (%s)' % u', '.join(details)
return retval
display_name = property(get_display_name, doc="""\
The localized display name of the locale.
>>> Locale('en').display_name
u'English'
>>> Locale('en', 'US').display_name
u'English (United States)'
>>> Locale('sv').display_name
u'svenska'
:type: `unicode`
""")
def get_language_name(self, locale=None):
"""Return the language of this locale in the given locale.
>>> Locale('zh', 'CN', script='Hans').get_language_name('de')
u'Chinesisch'
.. versionadded:: 1.0
:param locale: the locale to use
"""
if locale is None:
locale = self
locale = Locale.parse(locale)
return locale.languages.get(self.language)
language_name = property(get_language_name, doc="""\
The localized language name of the locale.
>>> Locale('en', 'US').language_name
u'English'
""")
def get_territory_name(self, locale=None):
"""Return the territory name in the given locale."""
if locale is None:
locale = self
locale = Locale.parse(locale)
return locale.territories.get(self.territory)
territory_name = property(get_territory_name, doc="""\
The localized territory name of the locale if available.
>>> Locale('de', 'DE').territory_name
u'Deutschland'
""")
def get_script_name(self, locale=None):
"""Return the script name in the given locale."""
if locale is None:
locale = self
locale = Locale.parse(locale)
return locale.scripts.get(self.script)
script_name = property(get_script_name, doc="""\
The localized script name of the locale if available.
>>> Locale('sr', 'ME', script='Latn').script_name
u'latinica'
""")
@property
def english_name(self):
"""The english display name of the locale.
>>> Locale('de').english_name
u'German'
>>> Locale('de', 'DE').english_name
u'German (Germany)'
:type: `unicode`"""
return self.get_display_name(Locale('en'))
# { General Locale Display Names
@property
def languages(self):
"""Mapping of language codes to translated language names.
>>> Locale('de', 'DE').languages['ja']
u'Japanisch'
See `ISO 639 <http://www.loc.gov/standards/iso639-2/>`_ for
more information.
"""
return self._data['languages']
@property
def scripts(self):
"""Mapping of script codes to translated script names.
>>> Locale('en', 'US').scripts['Hira']
u'Hiragana'
See `ISO 15924 <http://www.evertype.com/standards/iso15924/>`_
for more information.
"""
return self._data['scripts']
@property
def territories(self):
"""Mapping of script codes to translated script names.
>>> Locale('es', 'CO').territories['DE']
u'Alemania'
See `ISO 3166 <http://www.iso.org/iso/en/prods-services/iso3166ma/>`_
for more information.
"""
return self._data['territories']
@property
def variants(self):
"""Mapping of script codes to translated script names.
>>> Locale('de', 'DE').variants['1901']
u'Alte deutsche Rechtschreibung'
"""
return self._data['variants']
# { Number Formatting
@property
def currencies(self):
"""Mapping of currency codes to translated currency names. This
only returns the generic form of the currency name, not the count
specific one. If an actual number is requested use the
:func:`babel.numbers.get_currency_name` function.
>>> Locale('en').currencies['COP']
u'Colombian Peso'
>>> Locale('de', 'DE').currencies['COP']
u'Kolumbianischer Peso'
"""
return self._data['currency_names']
@property
def currency_symbols(self):
"""Mapping of currency codes to symbols.
>>> Locale('en', 'US').currency_symbols['USD']
u'$'
>>> Locale('es', 'CO').currency_symbols['USD']
u'US$'
"""
return self._data['currency_symbols']
@property
def number_symbols(self):
"""Symbols used in number formatting.
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('fr', 'FR').number_symbols['decimal']
u','
"""
return self._data['number_symbols']
@property
def decimal_formats(self):
"""Locale patterns for decimal number formatting.
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('en', 'US').decimal_formats[None]
<NumberPattern u'#,##0.###'>
"""
return self._data['decimal_formats']
@property
def currency_formats(self):
"""Locale patterns for currency number formatting.
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('en', 'US').currency_formats['standard']
<NumberPattern u'\\xa4#,##0.00'>
>>> Locale('en', 'US').currency_formats['accounting']
<NumberPattern u'\\xa4#,##0.00;(\\xa4#,##0.00)'>
"""
return self._data['currency_formats']
@property
def percent_formats(self):
"""Locale patterns for percent number formatting.
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('en', 'US').percent_formats[None]
<NumberPattern u'#,##0%'>
"""
return self._data['percent_formats']
@property
def scientific_formats(self):
"""Locale patterns for scientific number formatting.
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('en', 'US').scientific_formats[None]
<NumberPattern u'#E0'>
"""
return self._data['scientific_formats']
# { Calendar Information and Date Formatting
@property
def periods(self):
"""Locale display names for day periods (AM/PM).
>>> Locale('en', 'US').periods['am']
u'AM'
"""
try:
return self._data['day_periods']['stand-alone']['wide']
except KeyError:
return {}
@property
def day_periods(self):
"""Locale display names for various day periods (not necessarily only AM/PM).
These are not meant to be used without the relevant `day_period_rules`.
"""
return self._data['day_periods']
@property
def day_period_rules(self):
"""Day period rules for the locale. Used by `get_period_id`.
"""
return self._data.get('day_period_rules', {})
@property
def days(self):
"""Locale display names for weekdays.
>>> Locale('de', 'DE').days['format']['wide'][3]
u'Donnerstag'
"""
return self._data['days']
@property
def months(self):
"""Locale display names for months.
>>> Locale('de', 'DE').months['format']['wide'][10]
u'Oktober'
"""
return self._data['months']
@property
def quarters(self):
"""Locale display names for quarters.
>>> Locale('de', 'DE').quarters['format']['wide'][1]
u'1. Quartal'
"""
return self._data['quarters']
@property
def eras(self):
"""Locale display names for eras.
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('en', 'US').eras['wide'][1]
u'Anno Domini'
>>> Locale('en', 'US').eras['abbreviated'][0]
u'BC'
"""
return self._data['eras']
@property
def time_zones(self):
"""Locale display names for time zones.
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('en', 'US').time_zones['Europe/London']['long']['daylight']
u'British Summer Time'
>>> Locale('en', 'US').time_zones['America/St_Johns']['city']
u'St. John\u2019s'
"""
return self._data['time_zones']
@property
def meta_zones(self):
"""Locale display names for meta time zones.
Meta time zones are basically groups of different Olson time zones that
have the same GMT offset and daylight savings time.
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('en', 'US').meta_zones['Europe_Central']['long']['daylight']
u'Central European Summer Time'
.. versionadded:: 0.9
"""
return self._data['meta_zones']
@property
def zone_formats(self):
"""Patterns related to the formatting of time zones.
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('en', 'US').zone_formats['fallback']
u'%(1)s (%(0)s)'
>>> Locale('pt', 'BR').zone_formats['region']
u'Hor\\xe1rio %s'
.. versionadded:: 0.9
"""
return self._data['zone_formats']
@property
def first_week_day(self):
"""The first day of a week, with 0 being Monday.
>>> Locale('de', 'DE').first_week_day
0
>>> Locale('en', 'US').first_week_day
6
"""
return self._data['week_data']['first_day']
@property
def weekend_start(self):
"""The day the weekend starts, with 0 being Monday.
>>> Locale('de', 'DE').weekend_start
5
"""
return self._data['week_data']['weekend_start']
@property
def weekend_end(self):
"""The day the weekend ends, with 0 being Monday.
>>> Locale('de', 'DE').weekend_end
6
"""
return self._data['week_data']['weekend_end']
@property
def min_week_days(self):
"""The minimum number of days in a week so that the week is counted as
the first week of a year or month.
>>> Locale('de', 'DE').min_week_days
4
"""
return self._data['week_data']['min_days']
@property
def date_formats(self):
"""Locale patterns for date formatting.
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('en', 'US').date_formats['short']
<DateTimePattern u'M/d/yy'>
>>> Locale('fr', 'FR').date_formats['long']
<DateTimePattern u'd MMMM y'>
"""
return self._data['date_formats']
@property
def time_formats(self):
"""Locale patterns for time formatting.
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('en', 'US').time_formats['short']
<DateTimePattern u'h:mm a'>
>>> Locale('fr', 'FR').time_formats['long']
<DateTimePattern u'HH:mm:ss z'>
"""
return self._data['time_formats']
@property
def datetime_formats(self):
"""Locale patterns for datetime formatting.
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('en').datetime_formats['full']
u"{1} 'at' {0}"
>>> Locale('th').datetime_formats['medium']
u'{1} {0}'
"""
return self._data['datetime_formats']
@property
def datetime_skeletons(self):
"""Locale patterns for formatting parts of a datetime.
>>> Locale('en').datetime_skeletons['MEd']
<DateTimePattern u'E, M/d'>
>>> Locale('fr').datetime_skeletons['MEd']
<DateTimePattern u'E dd/MM'>
>>> Locale('fr').datetime_skeletons['H']
<DateTimePattern u"HH 'h'">
"""
return self._data['datetime_skeletons']
@property
def interval_formats(self):
"""Locale patterns for interval formatting.
.. note:: The format of the value returned may change between
Babel versions.
How to format date intervals in Finnish when the day is the
smallest changing component:
>>> Locale('fi_FI').interval_formats['MEd']['d']
[u'E d. \u2013 ', u'E d.M.']
.. seealso::
The primary API to use this data is :py:func:`babel.dates.format_interval`.
:rtype: dict[str, dict[str, list[str]]]
"""
return self._data['interval_formats']
@property
def plural_form(self):
"""Plural rules for the locale.
>>> Locale('en').plural_form(1)
'one'
>>> Locale('en').plural_form(0)
'other'
>>> Locale('fr').plural_form(0)
'one'
>>> Locale('ru').plural_form(100)
'many'
"""
return self._data.get('plural_form', _default_plural_rule)
@property
def list_patterns(self):
"""Patterns for generating lists
.. note:: The format of the value returned may change between
Babel versions.
>>> Locale('en').list_patterns['standard']['start']
u'{0}, {1}'
>>> Locale('en').list_patterns['standard']['end']
u'{0}, and {1}'
>>> Locale('en_GB').list_patterns['standard']['end']
u'{0} and {1}'
"""
return self._data['list_patterns']
@property
def ordinal_form(self):
"""Plural rules for the locale.
>>> Locale('en').ordinal_form(1)
'one'
>>> Locale('en').ordinal_form(2)
'two'
>>> Locale('en').ordinal_form(3)
'few'
>>> Locale('fr').ordinal_form(2)
'other'
>>> Locale('ru').ordinal_form(100)
'other'
"""
return self._data.get('ordinal_form', _default_plural_rule)
@property
def measurement_systems(self):
"""Localized names for various measurement systems.
>>> Locale('fr', 'FR').measurement_systems['US']
u'am\\xe9ricain'
>>> Locale('en', 'US').measurement_systems['US']
u'US'
"""
return self._data['measurement_systems']
@property
def character_order(self):
"""The text direction for the language.
>>> Locale('de', 'DE').character_order
'left-to-right'
>>> Locale('ar', 'SA').character_order
'right-to-left'
"""
return self._data['character_order']
@property
def text_direction(self):
"""The text direction for the language in CSS short-hand form.
>>> Locale('de', 'DE').text_direction
'ltr'
>>> Locale('ar', 'SA').text_direction
'rtl'
"""
return ''.join(word[0] for word in self.character_order.split('-'))
@property
def unit_display_names(self):
"""Display names for units of measurement.
.. seealso::
You may want to use :py:func:`babel.units.get_unit_name` instead.
.. note:: The format of the value returned may change between
Babel versions.
"""
return self._data['unit_display_names']
def default_locale(category=None, aliases=LOCALE_ALIASES):
"""Returns the system default locale for a given category, based on
environment variables.
>>> for name in ['LANGUAGE', 'LC_ALL', 'LC_CTYPE']:
... os.environ[name] = ''
>>> os.environ['LANG'] = 'fr_FR.UTF-8'
>>> default_locale('LC_MESSAGES')
'fr_FR'
The "C" or "POSIX" pseudo-locales are treated as aliases for the
"en_US_POSIX" locale:
>>> os.environ['LC_MESSAGES'] = 'POSIX'
>>> default_locale('LC_MESSAGES')
'en_US_POSIX'
The following fallbacks to the variable are always considered:
- ``LANGUAGE``
- ``LC_ALL``
- ``LC_CTYPE``
- ``LANG``
:param category: one of the ``LC_XXX`` environment variable names
:param aliases: a dictionary of aliases for locale identifiers
"""
varnames = (category, 'LANGUAGE', 'LC_ALL', 'LC_CTYPE', 'LANG')
for name in filter(None, varnames):
locale = os.getenv(name)
if locale:
if name == 'LANGUAGE' and ':' in locale:
# the LANGUAGE variable may contain a colon-separated list of
# language codes; we just pick the language on the list
locale = locale.split(':')[0]
if locale.split('.')[0] in ('C', 'POSIX'):
locale = 'en_US_POSIX'
elif aliases and locale in aliases:
locale = aliases[locale]
try:
return get_locale_identifier(parse_locale(locale))
except ValueError:
pass
def negotiate_locale(preferred, available, sep='_', aliases=LOCALE_ALIASES):
"""Find the best match between available and requested locale strings.
>>> negotiate_locale(['de_DE', 'en_US'], ['de_DE', 'de_AT'])
'de_DE'
>>> negotiate_locale(['de_DE', 'en_US'], ['en', 'de'])
'de'
Case is ignored by the algorithm, the result uses the case of the preferred
locale identifier:
>>> negotiate_locale(['de_DE', 'en_US'], ['de_de', 'de_at'])
'de_DE'
>>> negotiate_locale(['de_DE', 'en_US'], ['de_de', 'de_at'])
'de_DE'
By default, some web browsers unfortunately do not include the territory
in the locale identifier for many locales, and some don't even allow the
user to easily add the territory. So while you may prefer using qualified
locale identifiers in your web-application, they would not normally match
the language-only locale sent by such browsers. To workaround that, this
function uses a default mapping of commonly used langauge-only locale
identifiers to identifiers including the territory:
>>> negotiate_locale(['ja', 'en_US'], ['ja_JP', 'en_US'])
'ja_JP'
Some browsers even use an incorrect or outdated language code, such as "no"
for Norwegian, where the correct locale identifier would actually be "nb_NO"
(Bokmål) or "nn_NO" (Nynorsk). The aliases are intended to take care of
such cases, too:
>>> negotiate_locale(['no', 'sv'], ['nb_NO', 'sv_SE'])
'nb_NO'
You can override this default mapping by passing a different `aliases`
dictionary to this function, or you can bypass the behavior althogher by
setting the `aliases` parameter to `None`.
:param preferred: the list of locale strings preferred by the user
:param available: the list of locale strings available
:param sep: character that separates the different parts of the locale
strings
:param aliases: a dictionary of aliases for locale identifiers
"""
available = [a.lower() for a in available if a]
for locale in preferred:
ll = locale.lower()
if ll in available:
return locale
if aliases:
alias = aliases.get(ll)
if alias:
alias = alias.replace('_', sep)
if alias.lower() in available:
return alias
parts = locale.split(sep)
if len(parts) > 1 and parts[0].lower() in available:
return parts[0]
return None
def parse_locale(identifier, sep='_'):
"""Parse a locale identifier into a tuple of the form ``(language,
territory, script, variant)``.
>>> parse_locale('zh_CN')
('zh', 'CN', None, None)
>>> parse_locale('zh_Hans_CN')
('zh', 'CN', 'Hans', None)
The default component separator is "_", but a different separator can be
specified using the `sep` parameter:
>>> parse_locale('zh-CN', sep='-')
('zh', 'CN', None, None)
If the identifier cannot be parsed into a locale, a `ValueError` exception
is raised:
>>> parse_locale('not_a_LOCALE_String')
Traceback (most recent call last):
...
ValueError: 'not_a_LOCALE_String' is not a valid locale identifier
Encoding information and locale modifiers are removed from the identifier:
>>> parse_locale('it_IT@euro')
('it', 'IT', None, None)
>>> parse_locale('en_US.UTF-8')
('en', 'US', None, None)
>>> parse_locale('de_DE.iso885915@euro')
('de', 'DE', None, None)
See :rfc:`4646` for more information.
:param identifier: the locale identifier string
:param sep: character that separates the different components of the locale
identifier
:raise `ValueError`: if the string does not appear to be a valid locale
identifier
"""
if '.' in identifier:
# this is probably the charset/encoding, which we don't care about
identifier = identifier.split('.', 1)[0]
if '@' in identifier:
# this is a locale modifier such as @euro, which we don't care about
# either
identifier = identifier.split('@', 1)[0]
parts = identifier.split(sep)
lang = parts.pop(0).lower()
if not lang.isalpha():
raise ValueError('expected only letters, got %r' % lang)
script = territory = variant = None
if parts:
if len(parts[0]) == 4 and parts[0].isalpha():
script = parts.pop(0).title()
if parts:
if len(parts[0]) == 2 and parts[0].isalpha():
territory = parts.pop(0).upper()
elif len(parts[0]) == 3 and parts[0].isdigit():
territory = parts.pop(0)
if parts:
if len(parts[0]) == 4 and parts[0][0].isdigit() or \
len(parts[0]) >= 5 and parts[0][0].isalpha():
variant = parts.pop()
if parts:
raise ValueError('%r is not a valid locale identifier' % identifier)
return lang, territory, script, variant
def get_locale_identifier(tup, sep='_'):
"""The reverse of :func:`parse_locale`. It creates a locale identifier out
of a ``(language, territory, script, variant)`` tuple. Items can be set to
``None`` and trailing ``None``\\s can also be left out of the tuple.
>>> get_locale_identifier(('de', 'DE', None, '1999'))
'de_DE_1999'
.. versionadded:: 1.0
:param tup: the tuple as returned by :func:`parse_locale`.
:param sep: the separator for the identifier.
"""
tup = tuple(tup[:4])
lang, territory, script, variant = tup + (None,) * (4 - len(tup))
return sep.join(filter(None, (lang, script, territory, variant)))
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